They have sprays to stop chewing, biting, licking. It's bitter apple, and just a couple of licks normally stops the bad habit. But remember, apply it only to the areas shes licking, and DON'T lick it yourself. Ewwwww!
What I do with mine is just GENTLY push her face away and say, "No" in a very stern way. I may have to do it a couple of times, but she gets the idea. Also, you can also use the word "stop". Use their name before you say the word, as I say, "Sierra, no."
get a spray bottle with water in it and every time the dog licks you squirt him/her. but you have to get in the habit of carrying that bottle everywhere you go. it does not hurt them and after about two weeks they get the idea. also say "NO" every time you have to use the squirt bottle.